Gen 1 UMC, 2021 Model S

[loonsailor]

I just replaced my (totaled) 2015 Model S with a 2021 pre-refresh S, bought used directly from Tesla. The new-to-me car came with a cable in a rectangular case that goes from the Tesla to a US 120V outlet only. I have, from my old car, a Gen 1 UMC with a bunch of adapters.

At home I had a Gen 1 wall connector that worked fine with the 2015, but the newer car refused to charge from it. Tesla, as well as a local installer, told me that some of the old wall connectors (mine was vintage ~2012) won't work with new cars, so I replaced it with a new universal wall connector at home. However, I have a second home in the mountains that just has a NEMA 14-50 receptacle in the garage. With the old car, I used the gen 1 UMC to connect the car to the 14-50, and it worked just fine.

My question is, is my gen 1 UMC likely to work with the 2021 car (even though the gen 1 wall connector didn't), or do I need to buy something else, either a new UMC or some sort of wall connector for the second home?

 

[ucmndd]

The Gen 1 UMC works just fine with newer cars.

 

[BrokerDon]

My Gen 1 UMC that came with my 2015 MS P85D charges fine with an our dad's 2023 Model 3 LR. My Gen 1 UMC also charges faster than his current Gen UMC he bought with his 2023 M3.

My Gen 2 Tesla Wall Connector on 100A breaker has also charged every Tesla we've connected including a 2023 M3... and charges my 2015 MS P85D with dual 40A chargers at 80A (19.2kW) too. It's awesome.

 

[RDoc]

We're in a very similar situation to the OP. Our 2015 S was totaled and we bought a 2021 pre-refresh S. The Gen 2 mobile connector button will open the charge port door, however our old Gen 1 mobile connector is at best very flaky about opening the port. The Gen 1 will charge the car just fine at 40A, but won't open the charge port door most of the time. The charge port door will open by pushing it and from the console and with the Gen 2 connector button, just not with the Gen 1 button.

 

[gaswalla]

the button on the handle of the gen1 UMC wears out and hence it's not opening the charging port... not a big deal at all as you can open from inside or just hold down the trunk button on the key fob for a few seconds and the charge port will open... nicer to have 40 amps from gen1 vs 32amps from gen 2 (and best to have more amps from a wall connector)

 

[David99]

I believe Tesla replaced voluntarily all Gen 1 mobile chargers out with newer models. I think they they found a potential problem and just replaced them. It's worth asking them if they still do that. It will charge just fine, but the newer ones are safer.

 

[RDoc]

the button on the handle of the gen1 UMC wears out and hence it's not opening the charging port... not a big deal at all as you can open from inside or just hold down the trunk button on the key fob for a few seconds and the charge port will open... nicer to have 40 amps from gen1 vs 32amps from gen 2 (and best to have more amps from a wall connector)

Doesn't it seem a bit too much of a coincidence though that 2 weeks ago it worked perfectly with our 2015 and now with no intervening uses it fails on our 2021?

 

[ucmndd]

Doesn't it seem a bit too much of a coincidence though that 2 weeks ago it worked perfectly with our 2015 and now with no intervening uses it fails on our 2021?

They just wear out. Only so many button presses in these things. Sure, maybe there’s something about your 2021 that makes it more flaky or doesn’t want to play nice with the old UMC, but it is what it is and there’s nothing to be done about it. My money is on “dying button”.

 

[ucmndd]

I believe Tesla replaced voluntarily all Gen 1 mobile chargers out with newer models.

First I’ve heard of this, would be surprised if it was ever a thing and VERY surprised if it still was.

 

[David99]

First I’ve heard of this, would be surprised if it was ever a thing and VERY surprised if it still was.

They took mine and gave me a new one. That was back in 2014/15. Did you have a Tesla back then?

 

[ucmndd]

They took mine and gave me a new one. That was back in 2014/15. Did you have a Tesla back then?

I got my Model S in 2016.

The Gen 2 UMC didn’t even exist until 2018 - so if they replaced yours in 2014/2015 they presumably just replaced it with another Gen 1? As I understand it they were covered under the new vehicle warranty so if one crapped out during that time I’m not surprised they’d just replace it.

 

[gaswalla]

the first (2012-2013) gen1 UMC's had issues with overheating and melting at the adapter site. Tesla did trade them out for ones with new adapters - still UMC Gen1.
Gen 2 came out in 2018 with the wide launch of Model 3 and limited charging to 32 amps as well as bringing in new design with new adapters.

 

[Rocky_H]

I believe Tesla replaced voluntarily all Gen 1 mobile chargers out with newer models. I think they they found a potential problem and just replaced them. It's worth asking them if they still do that. It will charge just fine, but the newer ones are safer.

No, they did not.

They took mine and gave me a new one. That was back in 2014/15. Did you have a Tesla back then?

I've had mine since March of 2014. Tesla never replaced or offered to replace my Gen1 UMC. What you may be thinking of is just the adapter plugs.

the first (2012-2013) gen1 UMC's had issues with overheating and melting at the adapter site. Tesla did trade them out for ones with new adapters - still UMC Gen1.

Yes, this is what they did. It was a recall and replace of some of the adapter plugs, where they shipped out new ones that could be identified by the grey face plastic on them and asked people to send back in their old ones.

 

[islandbayy]

They took mine and gave me a new one. That was back in 2014/15. Did you have a Tesla back then?

No gen 2 until about 2018. They did a recall/replacement on the 14-50 adapters. The replacement had a thermistor in it as they were overheating due to poorly wired 14-50 outlets.
No recall on Gen 1 UMC's themselves. Possibly they eventually replaced it with a Gen 2, if your vehicle was under warranty.

 

[David99]

I looked back at some records. I was wrong about the dates. It was in 2018. But they did give me a new Gen 2 and took my Gen 1. I don't know if I was lucky or just a thing in California.

 

[gaswalla]

I’d be upset if they took my gen1 and gave me gen2. 40amps vs 32 amps.

 

[islandbayy]

I’d be upset if they took my gen1 and gave me gen2. 40amps vs 32 amps.

I would be too. The Gen 1 was fine for the long term if you turned the amperage down to 32 or less. I went through a LOT of them (Burned out) before I figured that out. Using the 40 amp only when I NEEDED it. The heat build up was too great. Since I started turning the amperage down, I haven't burned out out in 6 or so years.
I've been snatching the Gen 1's up on Facebook and Craigslist for cheap now. Got a nice stockpile of them (5 or so) on my "tesla shelf" in the garage, as well as one in each car in the carry case each with the full assortment of adapters, as well as one loose cable I use as my main when charging via UMC (Wear one out at a time!)

 

[gaswalla]

^that’s exactly right. Only use max amperage when you “need” it

 

[ran349]

I would be too. The Gen 1 was fine for the long term if you turned the amperage down to 32 or less. I went through a LOT of them (Burned out) before I figured that out. Using the 40 amp only when I NEEDED it. The heat build up was too great. Since I started turning the amperage down, I haven't burned out out in 6 or so years.
I've been snatching the Gen 1's up on Facebook and Craigslist for cheap now. Got a nice stockpile of them (5 or so) on my "tesla shelf" in the garage, as well as one in each car in the carry case each with the full assortment of adapters, as well as one loose cable I use as my main when charging via UMC (Wear one out at a time!)

They must have made some of the Gen 1 cables better than others. I have used mine every day for over 8 years and always charge at 40 amps.
I can barely feel it warm at the end of charging. Maybe I just got lucky in that regard.

 

[islandbayy]

They must have made some of the Gen 1 cables better than others. I have used mine every day for over 8 years and always charge at 40 amps.
I can barely feel it warm at the end of charging. Maybe I just got lucky in that regard.

Possibly. The worst failure though was the first one.... 2013, 2 weeks after delivery....While I was 200 miles from home by my parents.... With only ~5 J1772 stations in the ENTIRE STATE of Wisconsin..... Thankfully, Tesla was a MUCH different company back then, and overnighted me a replacement UMC.
The later/last revision of Gen 1's were much better though, yes. Gen 2 is pretty much just a physically redesigned Gen 1, same internal hardware for the most part, that is just hard limited to 32 amp max.
It was heat buildup that was killing them. I think many, it was cooked power relays. A friend's Gen 1 "died" last summer. I didn't hear any click when it was powered up. Gave it a nice SMACK on the concrete, which freed up the relay, plugged it in and he's been using it since, with the caveat to keep it at or below 32 amps.